Various vehicle components are known to transmit energy from collisions to vehicle occupants. A typical component is a steering column of a steering wheel that includes a housing or mask jacket that collapses during a vehicle collision. The mask jacket translates the collision energy through an energy absorber to convert the crash energy to a fraction of the kinetic energy transferred to the vehicle operator.
A common energy absorber transmits force created by a plastic deformation of a metal element or strap disposed in the energy absorber. An example is disclosed in U.S. Pat. No. 6,322,103 where deformation of a flat metal strap over an anvil is disclosed to absorb crash energy. It has been discovered that a benefit is derived by adjusting the amount of energy absorbed relative to the amount of energy that may be translated to the vehicle operator based on such variables as vehicle speed, vehicle weight, and operator weight. Also, U.S. Pat. No. 6,189,929 discloses an anvil having various diameters where the anvil is adjusted to position a desired diameter in contact with the metal strap to adjust the amount of energy absorption produced by the energy absorber.
While these devices are capable of producing various amounts of energy absorption, they have not provided a desirable degree of variable energy absorption. Further, these devices are known to provide an imprecise amount of energy absorption relative to the desired amount of energy absorption due to mechanical failures such as, for example “bounce back” where the anvil is initially moved to a desirable position but rebounds back to an initial position. Therefore, it would be desirable to provide an energy absorber having both an increased degree of variable energy absorption along with a more accurate degree of energy absorption.